Abstract

BACKGROUND: The aim of our study was to determine whether various anatomic factors constitute a predisposition to a lower pole renal stones. METHODS: We analysed the computed tomography (CT) urography of 75 patients with a single lower pole stone. Measurements were taken of the infundibulopelvic angle (IPA),infundibular width (IW), infundibular length (IL) and calyceopelvic height (CPH). RESULTS: The mean patient age was 50 years (range 17-79). The mean stone size was 11.9 mm. The mean IPA using Sampaio method in affected kidney was 113.4 ± 15.3o (range 80-139o), 59.5 ± 17.3o using Elbahnasy method. The values of IPA on the contralateral kidney were 119.86 ± 15.37o (range 79-141 ͦ ; p = 0.001) using Sampaio method of measurement and 59.78 ± 12o (range 34-90 ͦ ; p = 0.465) using the method described by Elbahnasy. We reported statistically significant differences between stone-bearing kidney and contralateral kidney in measurement IPA using only Sampaio method. The mean infundibular width was 4.22 ± 1.81 mm on the affected kidney and 3.72 ± 2.5 mm on the contralateral side (p = 0.164). The mean infundibular length was 15.37 ± 4.57 mm on the affected kidney and 14.66 ± 4.35 mm on the unaffected side (p = 0.329).The CPH was 10.19 ± 4.05 mm on the affected kidney and 10.44 ± 3.83 mm on the normal side (p = 0.688). CONCLUSIONS: Pelvicaliceal morphology of the kidney is one of the factors that determine the risk of developing kidney stones. Out of the analysed morphological parameters of kidney IPA is a statistically significant risk factor to form lower pole kidney stones. Other anatomic parameters did not seem to have a significant role in predisposing to form lower pole kidney stone.

Kommentare
1

Although the title of this manuscript has its focus on the relationship between lower calyx anatomy and stone formation, parts of the discussion comes back to the problem of stone clearance after stone removal with modern techniques. Obviously both fragment clearance and stone formation/development seem to depend on similar anatomical and geometrical properties of the lower calyx. That is the main message of the article and little attention is paid to stone forming process and how that process is affected by the geometry.

The difficulties of accurately determining the angles between the lower calyx infundibulum and the renal pelvis are apparent from this report. This was a tricky process already when standard urography was used. This measurement became more difficult when contrast urographies were replaced by CT examination with contrast. With NCCT such measurements are even more demanding and less accurate.

It is my assumption that development of stones in the lower calyx might be explained by gravitation and if this is the case it seems more relevant (and much easier) to determine the angle between the lower calyx and a vertical line as suggested in a previous publication on fragment clearance [1].

Although the title of this manuscript has its focus on the relationship between lower calyx anatomy and stone formation, parts of the discussion comes back to the problem of stone clearance after stone removal with modern techniques. Obviously both fragment clearance and stone formation/development seem to depend on similar anatomical and geometrical properties of the lower calyx. That is the main message of the article and little attention is paid to stone forming process and how that process is affected by the geometry.
The difficulties of accurately determining the angles between the lower calyx infundibulum and the renal pelvis are apparent from this report. This was a tricky process already when standard urography was used. This measurement became more difficult when contrast urographies were replaced by CT examination with contrast. With NCCT such measurements are even more demanding and less accurate.
It is my assumption that development of stones in the lower calyx might be explained by gravitation and if this is the case it seems more relevant (and much easier) to determine the angle between the lower calyx and a vertical line as suggested in a previous publication on fragment clearance [1].
Reference
1. Leykamm L,Tiselius HG Observations on inrarenal geometry of the lower-caliceal system in relation to clearance of stone fragments after extracorporeal shock wave lithotripsy. J Endourol. 2007; 21: 386-392.